Pakalniai Hill Fort, also known as the Swedish Battery, is an impressive archaeological site located on the southwestern shore of Lake Vidinksas. This hill fort dates back to the late 1st millennium BC and the 2nd millennium BC. It features a rectangular platform measuring 48 by 41 meters, elongated in a north-south direction. Within the platform, there is a cultural layer up to 35 cm thick, composed of dark soil, containing post holes, remnants of hearths, and various archaeological finds.
A cross was erected at the top of the hill fort in 1918, which was restored in 1989 and 1998. There are also four partisans' graves here, commemorating the history of the area. The slopes are steep, reaching a height of 25 meters, and exhibit a well-preserved system
of defensive ditches and embankments. At the foot of the hill fort, there was once an ancient settlement where archaeologists found valuable artifacts.
According to local legends, the hill fort was raised by water nymphs using their aprons. Other tales suggest that it was created by people wearing iron caps, as it was believed that a church or castle might be hidden there. It is said that on Easter, the hill would open up, and people would walk around it, witnessing gold burning on the hill and in the fields.
Nearby, there is also a round Laumės (Nymph) mound, which is protected as a cultural heritage site. This area, rich in history and legends, has been declared a cultural monument in recognition of its significance and historical value.